Reaction Steps
Sodium hydride (1.96 g, 49.337 mmol, 60% suspension in mineral oil) was treated with DMF (60 mL), followed by 6-nitroindole (6) (2.0 g, 12.334 mmol) in DMF (20 mL) over a period of 5 min at 0° C. After stirring for 15 min, the solution was treated with 1-chloro-3-iodopropane (3.9 mL, 37.002 mmol), the reaction was brought to room temperature and stirred for 3 h. The reaction was quenched with saturated brine (80 mL), water (80 mL) and cooled to 0° C. The solid was filtered off, washed with water (50-75 mL) and dried to obtain the crude product. The crude product was recrystallised from hot toluene (10 mL)/hexanes (5 mL) to obtain compound 148 (2.637 g, 90%) as solid. mp 85-87° C.; 1H-NMR (CDCl3) δ 2.28-2.36 (m, 2H), 3.46 (t, 2H, J=5.7 Hz), 4.45 (t, 2H, J=6.6 Hz), 6.62 (d, 1H, J=2.7 Hz), 7.43 (d, 1H, J=3.0 Hz), 7.66 (d, 1H, J=8.7 Hz), 8.02 (dd, 1H, J=1.8, 7.9 Hz), 8.36 (d, 1H, J=0.9 Hz). 1-(3-Morpholin-4-yl-propyl)-6-nitro-1H-indole (149): A solution of compound 148 (2.35 g, 9.845 mmol) in dry CH3CN (40 mL) was treated with K2CO3 (13.6 g, 98.458 mmol), KI (16.3 g, 98.458 mmol) and morpholine (8.58 mL, 98.458 mmol) at room temperature. The resulting mixture was refluxed for overnight (15 h). The reaction was brought to room temperature and the solvent was evaporated. The mixture was diluted with water (100 mL) and extracted with ethyl acetate (2×50 mL). The combined ethyl acetate layer was washed with water (25 mL), brine (20 mL) and dried (Na2SO4). The solvent was evaporated under reduced pressure and the crude product was purified by column chromatography (EtOAC: 2M NH3 in methanol/CH2Cl2, 1:1) to obtain compound 149 (2.85 g, quantitative) as a syrup. 1H-NMR (CDCl3) δ 1.97-2.06 (m, 2H), 2.23 (t, 2H, J=6.3 Hz), 2.38 (brs, 4H), 3.75 (t, 4H, J=4.5 Hz), 4.33 (t, 2H, J=6.6 Hz), 6.59 (d, 1H, J=3.0 Hz), 7.39 (d, 1H, J=3.0 Hz), 7.64 (d, 1H, J=8.7 Hz), 8.00 (dd, 1H, J=1.8, 8.7 Hz), 8.42 (brs, 1H). N-[1-(3-Morpholin-4-yl-propyl)-1H-indol-6-yl]-thiophene-2-carboxamidine (150): A solution of compound 149 (2.0 g, 6.912 mmol) in abs. ethanol (20 mL) was treated with Pd—C (0.25 g), purged with hydrogen gas and stirred for overnight (15 h) under hydrogen atm. (balloon pressure). The reaction mixture was filtered through a celite pad and washed with abs. ethanol (2×20 mL). The combined ethanol layer was treated with thiophene-2-carboximidothioic acid methyl ester hydroiodide (3.94 g, 13.824 mmol) and the resulting mixture was stirred for overnight (16 h) at room temperature. The solvent was evaporated and the product was precipitated with ether (250 mL). The solid was dissolved into sat. NaHCO3 sol.:CH2Cl2 (100 mL, 1:1). The org. layer was separated and aqueous layer was extracted with CH2Cl2 (2×50 mL). The combined CH2Cl2 layer was washed with brine (25 mL) and dried (Na2SO4). The solvent was evaporated and the crude product was purified by column chromatography (2M NH3 in methanol: CH2Cl2, 5:95) to obtain compound 150 (2.348 g, 92%) as a foam. 1H-NMR (DMSO-d6) δ 1.83-1.91 (m, 2H), 2.19 (t, 2H, J=6.6 Hz), 2.30 (brs, 4H), 3.56 (t, 4H, J=4.8 Hz), 4.14 (t, 2H, J=6.6 Hz), 6.34-6.35 (m, 3H), 6.58 (dd, 1H, J=1.2, 8.2 Hz), 6.95 (brs, 1H), 7.09 (dd, 1H, J=3.9, 5.1 Hz), 7.21 (d, 1H, J=3.0 Hz), 7.44 (d, 1H, J=8.1 Hz), 7.59 (d, 1H, J=3.9 Hz), 7.72 (dd, 1H, J=0.9, 3.6 Hz). Hydrochloride salt of N-[1-(3-morpholin-4-yl-propyl)-1H-indol-6-yl]-thiophene-2-carboxamidine (151): A solution of compound 150 (0.65 g, 1.763 mmol) in methanol (5 mL) was treated with 1 N HCl in ether (5.3 mL, 5.291 mmol) at 0° C. The reaction was brought to room temperature and stirred for 30 min. The solvent was evaporated and the crude product was recrystallized from ethanol/ether to obtain compound 151 (0.66 g, 85%) as a solid. mp 100-105° C. ESI-MS m/z (%): 369 (M+, 100).
